To assess the c-kit mutation rate in samples from patients with other types of leukemia, the novel method was used to analyze 95 non-CBF-AML samples, including 58 AML (negative for AML1-ETO and CBFB-MYH11), 25 acute lymphoblastic leukemia, 10 chronic myelocytic leukemia and two chronic eosinophilic leukemia samples. The gene discussed is CBFB; the disease is Chronic Eosinophilic Leukemia, Not Otherwise Specified.